Using an Engineer's Ruler
An Engineering scale, also known as an engineer's ruler, is used by engineers, construction personnel, and others who need to measure details on a blue print or engineering drawing. Blueprints and construction drawings are always drawn and plotted at a standard scale. With modern computer aided design (CAD) programs like AutoCAD and MicroStation, drawings are created at full-scale in model space. To prepare a drawing for plotting, the model is then ported to paper space view at a standard engineering scale. Typical standard scales are measured in number of feet represented by 1 inch. For example, 1"=10', 1"=20', 1"=30', 1"=40', 1"=50', and 1"=60' are all standard plotting scales.
2. Match up the drawing scale with the equivalent side of the engineering scale. Lay the ruler down on the drawing scale graphic to verify the scale. Sometimes drawings are plotted at the wrong scale. If the graphic does not match up exactly, measurements using the scale will not be precise. Another check to see if the sheet was plotted correctly is by checking a known distance on the plan sheet. Look for stationing or a dimension detail and measure it using the engineering scale to see if it is correct.
1. Find the drawing scale on the blueprint or construction drawing. The scale is typically located in the upper right or lower right corner of the sheet. The drawing scale is typically noted as "horizontal scale in feet". Many times, the designer will use a 1 inch graphic indicating the number of feet equal to 1 inch.
3. Measure the desired detail on the drawing using the scale determined from step 2. Lay the ruler down on the drawing and determine the measurement in number of feet. Remember to check every sheet for the scale on each drawing. Each sheet may be different and different views on each sheet may also vary.